Grain carts are commonly used in agriculture to aid in the harvesting of various agricultural crops including grain, corn, beans or other crops generally referred to herein as particulate material. A grain cart typically comprises a storage bin supported on wheels for towing behind a towing vehicle, for example a tractor, having a power takeoff shaft. An unload auger is typically located at one end of the storage bin to discharge material from the bin upwardly and to one side of the bin. A lower auger is commonly located within the bottom of the bin to move particulate material in the bin towards the bottom end of the unload auger. Examples of grain carts of this type can be found in US patent application publications US 2011/0164952 by Hollenberg and US 2015/0203019 by Kinzenbaw. As best shown in Hollenberg, one prior art means of driving rotation of the augers is to provide a driveshaft extending the length of the grain cart from the power takeoff shaft in front of the grain cart to a transfer case at the rear of the grain cart to drive the lower auger from the rear end thereof. The drive can be transferred from the lower auger to the unload auger by a separate drive connection between a singular input connected to the lower auger and a singular output connected to the unload auger. Use of a driveshaft extending the length of the grain cart can interfere with ground clearance, and thus requires the bottom end of the storage bin locating the lower auger therein to be raised a considerable distance from the ground to accommodate the driveshaft, resulting in poor stability of the overall grain cart.
Alternatively, in a more traditional dual auger system, the horizontal auger sits slightly above the vertical auger axis pushing the grain from the tank and dropping it onto the vertical auger inside a transition housing. The drive system for the dual auger system consists of a drive shaft that drives a right-angle gearbox to drive the vertical flighting. On the input pinion shaft of the gearbox, a pulley is mounted which drives a rubber belt which rotates the pulley that is mounted to the horizontal flighting that reaches along the floor of the tank in the grain cart. In this instance, the minimum distance of the axes is determined by the radius of the vertical auger flighting plus the radius of the horizontal auger drive shaft. The unload auger is capable of pivoting up and down from the axis of the horizontal drag auger. Furthermore, a gearbox and adjacent housing creates a minimum sweep radius R that must be cleared by the hitch frame members and not be vulnerable to striking objects on the ground or contacting the hitch frame members during pivoting motion. It is desired by the customers to have available either a left hand or right hand option to allow for a more comfortable operation based on their preference. Traditionally this is only possible with specific auger tubes that must be created for both left hand and right and unloading setups. Customers may prefer one option over the other so being able to accommodate both options will require a different build of auger and ultimately different build of cart.